Abstract
We report a case of gastrointestinal stromal tumor (GIST) of the ileum in which complete remission (CR) on computed tomography (CT) scan was achieved by imatinib mesylate treatment. In October 2000, a 70-year-old man visited our hospital, complaining of lower abdominal pain. A contrast abdominal CT showed a 15-cm tumor with solid and cystic components and a clear margin. A communication between a tumor and intestinal lumen was found in intestinal series and a CT with gastrografin contrast. The tumor was resected along with adjacent intestine. Immunohistochemistry showed positive staining for c-kit and CD34, and the diagnosis of GIST was confirmed. Peritoneal recurrence was observed 3 times in the next 3 years and the recurrent tumors were surgically removed. At the 3rd recurrence, multiple hepatic metastases were found. Because genetic analysis revealed the sequence variation in exon11 of the c-kit, the main tumors were surgically removed and imatinib mesylate treatment was selected for residual tumors in September 2003. After a 1-month of imatinib 300mg per day, reduction of tumors was confirmed. Imatinib mesylate was increased to 400mg per day. After a 10-month treatment, CR of the recurrent tumors and hepatic metastases was confirmed on CT. Imatinib mesylate treatment was continued. No side effects have been observed up to April 2005.
